Ligation is a well known technique for treating various types of tissue defects and lesions including varices and hemorrhoids. A target region of tissue containing the vessel can be ligated by applying an elastic cord or band to the tissue. The band stops the circulation of blood through the vessel and causes the ligated tissue to necrose and slough off. Ligation has proved to be somewhat successful in the treatment of esophageal varices.
Esophageal varices are dilated or enlarged blood vessels within the wall of the esophagus. Esophageal varices are most frequently found in the lower part of the esophagus and are usually the result of obstructed blood flow through the portal vein, which carries blood from the intestine and the spleen to the liver. A common cause of this obstruction is liver disease, such as cirrhosis. For example, patients with cirrhosis develop portal hypertension which causes blood flow through the liver to be diminished. As blood flow through the liver is decreased, blood flow through the microscopic blood vessels within the esophageal wall is increased. This increase in flow causes the blood vessels to dilate. In some cases, an esophageal varix can be as large as 0.5 to 1.0 cm or larger in diameter. Other causes of esophageal varices include blood clots in the portal vein and any condition that increases pressure in the portal vein such as severe congestive heart failure. Esophageal varices cause no symptoms until they become large enough to rupture and bleed. Bleeding from esophageal varices is a life-threatening condition that requires immediate medical treatment.
Endoscopic variceal ligation is an established procedure used to treat esophageal varices before a rupture occurs and is based on a technique initially used for the band ligation of hemorrhoids. This technique involves applying small, elastic “O” rings or bands to a target region of tissue to thereby mechanically ligate and strangulate the variceal channels. The application of the ligation bands to a varix is typically accomplished by means of a device attached to a distal end of an endoscope. Endoscopic variceal ligation is somewhat successful at treating esophageal varices, but one drawback of endoscopic variceal ligation is that varices frequently recur after being treated.
While several devices are available for performing various ligation procedures, a need exists for methods and devices for ligating and coagulating a target region of tissue.